Diffusion of Acceptor Metal Impurities from Semi‐Insulating GaN into Undoped GaN Epitaxial Layers

Acceptor diffusion in two‐dimensional electron gas (2DEG) of GaN/AlGaN high‐electron‐mobility transistors degrades the electric performance of devices, such as 2DEG mobility and on‐resistance. Herein, the diffusion of Fe, C, and Mn in GaN grown by hydride vapor‐phase epitaxy and metal–organic chemical vapor deposition at 1000 °C was evaluated which determined their diffusion coefficients. C exhibited minimal diffusion in GaN at 1000 °C, while Mn exhibited an order of magnitude higher diffusion coefficient than Fe. An acceptor diffusion prevention layer comprising C‐doped GaN with a concentration of 1 × 10 17 cm −3 was tested that effectively prevented Fe and Mn diffusion. Thus, the 1 × 10 17 cm −3 GaN:C layer prevented the acceptors Fe and Mn from diffusing in GaN.